567 research outputs found
Estructura de la propiedad y poblamiento en Milpa Alta 1917-1960
Proyecto Terminal (Licenciatura en SociologĂa) -- Universidad AutĂłnoma Metropolitana, Unidad Azcapotzalco, DivisiĂłn de Ciencias Sociales y Humanidades, Departamento de SociologĂa, 2006. UAMADCSHDS 1 archivo PDF (95 pĂĄginas
Load Distribution on PET-G 3D Prints of Honeycomb Cellular Structures under Compression Load.
Energy resulting from an impact is manifested through unwanted damage to objects or persons. New materials made of cellular structures have enhanced energy absorption (EA) capabilities. The hexagonal honeycomb is widely known for its space-filling capacity, structural stability, and high EA potential. Additive manufacturing (AM) technologies have been effectively useful in a vast range of applications. The evolution of these technologies has been studied continuously, with a focus on improving the mechanical and structural characteristics of three-dimensional (3D)-printed models to create complex quality parts that satisfy design and mechanical requirements. In this study, 3D honeycomb structures of novel material polyethylene terephthalate glycol (PET-G) were fabricated by the fused deposition modeling (FDM) method with different infill density values (30%, 70%, and 100%) and printing orientations (edge, flat, and upright). The effectiveness for EA of the design and the effect of the process parameters of infill density and layer printing orientation were investigated by performing in-plane compression tests, and the set of parameters that produced superior results for better EA was determined by analyzing the area under the curve and the welding between the filament layers in the printed object via FDM. The results showed that the printing parameters implemented in this study considerably affected the mechanical properties of the 3D-printed PET-G honeycomb structure. The structure with the upright printing direction and 100% infill density exhibited an extension to delamination and fragmentation, thus, a desirable performance with a long plateau region in the load-displacement curve and major absorption of energy
Materials Supply System Analysis Under Simulation Scenarios in a Lean Manufacturing Environment
AbstractIdentifying the most efficient supply system for a company working under Lean Manufacturing practices was possible with the support of this work. Promodel software was used to develop simulation model depicting a constant velocity joints (CVJ) production system, where two different supply methods were assessed. According to results herein obtained, better performance is achieved under random supply method in comparison with a clustering supply method. The companyâs goal is to keep 1% losses due to lack of material. In the actual process, this essential parameter was reduced from 2.73% to 1.177%, if random supply method is properly implemented
Recovery of the physiological status in professional basketball players using NESA neuromodulation treatment during different types of microcycles in season: A preliminary randomized clinical trial.
The purpose of the study was to describe and compare recovery status after official basketball competition in players who underwent NESA neuromodulation treatment (NNT) in weeks with one or two matches. The recovery parameters of 12 professional male basketball players (mean ± SD, age: 20.6 ± 2.7 yr; height: 197.8 ± 11.7 cm; and body mass: 89.0 ± 21.2 kg) that competed in the LEB Plata (Spanish third division) were monitored 2 days after match-play over 6 weeks, and included: 1) the Hooper Test, which combines four subjective variables (sleep, stress, fatigue and soreness); 2) common biochemical markers (e.g., testosterone, cortisol and ratio T:C); and 3) lowest heart rate [HR], average HR, HR variability, sleep duration, awake time during night and onset latency before asleep). Players that completed NNT presented differences compared to the control group in sleep data. For instance, the lowest HR (p < 0.001), average HR (p < 0.001) and total awake time (p = 0.04) were significantly reduced in the NNT group. On the contrary, the control group presented greater values than the NNT group in the subjective Hooper Test, although only stress presented significant differences (Control 2.5 ± 1.2 vs. NNT cost or 3.2 ± 0.9; p = 0.01). Additionally, there were no significant differences in recovery parameters between weeks with one or two matches. In conclusion, the results suggest that players that underwent NNT tended to improve their sleep quality. Nevertheless, playerâs values in the biochemical markers and wellness status remained similar in both groups. The fact that no significant differences were found between weeks with one or two matches could help basketball professionals to determine that a congested schedule does not seem to negatively alter recovery status.post-print1317 K
Selection on dispersal drives evolution of metabolic capacities for energy production in female wing-polymorphic sand field crickets, Gryllus firmus
Life history and metabolism covary, but the mechanisms and individual traits responsible for these linkages remain unresolved. Dispersal capability is a critical component of life histories that is constrained by metabolic capacities for energy production. Conflicting relationships between metabolism and life histories may be explained by accounting for variation in dispersal and maximal metabolic rates. We used female wing-polymorphic sand field crickets, Gryllus firmus, selected either for long wings (LW) and flight-capability or short wings (SW) and high early lifetime fecundity to test the hypothesis that selection on dispersal capability drives the evolution of metabolic capacities. While resting metabolic rates were similar, long-winged crickets reached higher maximal metabolic rates than short-winged crickets, resulting in improved running performance. We further provided insight into the mechanisms responsible for covariation between life history and metabolism by comparing mitochondrial content of tissues involved in powering locomotion and assessing function of mitochondria isolated from long- and short-winged crickets. This demonstrated that larger metabolic capacities in long-winged crickets were underpinned by increases in mitochondrial content of dorsoventral flight muscle and enhanced bioenergetic capacities of mitochondria within the fat body, a tissue responsible for fuel storage and mobilization. Thus, selection on flight-capability remodels metabolism in a trait and tissue-specific manner to enlarge metabolic capacities necessary for dispersal
Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses
Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats
Use of AndromedÂź and OviXcellÂź diluents in the processing of sheep semen with the addition of HTF
Objective: To assess the effect of two ovine semen diluents, AndromedÂź and OviXcellÂź, on the mass motility, vitality, and acrosomal integrity of spermatozoa processed at different temperatures and with the addition of post-thawed HTF (human tubal fluid).
Design/Methodology/Approach: Semen from 2 Dorper ram was used. Four ejaculations per male were collected and diluted with AndromedÂź and OvixcellÂź. There were four treatments with OvixcellÂź: 1) fresh OvixcellÂź, 2) refrigerated OvixcellÂź, 3) post-thawed OvixcellÂź, and 4) post-thawed OvixcellÂź + HTF. Four treaments with AndromedÂź were also carried out: 1) fresh AndromedÂź, 2) refrigerated AndromedÂź, 3) post-thawed AndromedÂź, and 4) post-thawed AndromedÂź + HTF. Mass motility, vitality, and acrosomal integrity were performed with a CASA computer system and statistically analyzed with the GLM procedure of the SAS software.
Results: When the effect of OvixcellÂź mass motility was assessed, the following results were obtained, with differences (pË0.05) between treatments: 87% in fresh semen, 72% refrigerated semen, 55% in post-thawed semen, and 68% in post-thawed semen + HTF. A clear difference (pË0.05) was observed when HTF was added to post-thawed semen (13%). AndromedÂź behaved in the same way as OvixcellÂź (pË0.05) and a 18% recovery was observed with the addition of HTF. A high percentage of live spermatozoa with intact acrosome was observed for fresh semen (97.8%), while it diminished (p<0.05) as the temperature of refrigerated and frozen semen gradually decreased.
Study Limitations/Implications: More experimental units should be used, despite the increase in maintenance costs per animal.
Findings/Conclusions: The use of AndromedÂź and OviXcellÂź diluents was satisfactory in relation to the mass motility, vitality, and acrosomal integrity in spermatozoa processed at different temperatures (fresh, refrigerated, and post-thawed). Furthermore, the addition of HTF increased post-thawed mass motility
Analyzing multitarget activity landscapes using protein-ligand interaction fingerprints: interaction cliffs.
This is the original submitted version, before peer review. The final peer-reviewed version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ci500721x.Activity landscape modeling is mostly a descriptive technique that allows rationalizing continuous and discontinuous SARs. Nevertheless, the interpretation of some landscape features, especially of activity cliffs, is not straightforward. As the nature of activity cliffs depends on the ligand and the target, information regarding both should be included in the analysis. A specific way to include this information is using protein-ligand interaction fingerprints (IFPs). In this paper we report the activity landscape modeling of 507 ligand-kinase complexes (from the KLIFS database) including IFP, which facilitates the analysis and interpretation of activity cliffs. Here we introduce the structure-activity-interaction similarity (SAIS) maps that incorporate information on ligand-target contact similarity. We also introduce the concept of interaction cliffs defined as ligand-target complexes with high structural and interaction similarity but have a large potency difference of the ligands. Moreover, the information retrieved regarding the specific interaction allowed the identification of activity cliff hot spots, which help to rationalize activity cliffs from the target point of view. In general, the information provided by IFPs provides a structure-based understanding of some activity landscape features. This paper shows examples of analyses that can be carried out when IFPs are added to the activity landscape model.M-L is very
grateful to CONACyT (No. 217442/312933) and the Cambridge Overseas Trust for funding. AB
thanks Unilever for funding and the European Research Council for a Starting Grant (ERC-2013-
StG-336159 MIXTURE). J.L.M-F. is grateful to the School of Chemistry, Department of
Pharmacy of the National Autonomous University of Mexico (UNAM) for support. This work
was supported by a scholarship from the Secretariat of Public Education and the Mexican
government
Reading Between the (Spectral) Lines: Magellan/IMACS spectroscopy of the Ultra-faint Dwarf Galaxies Eridanus IV and Centaurus I
We present a spectroscopic analysis of Eridanus IV (Eri IV) and Centaurus I
(Cen I), two ultra-faint dwarf galaxies of the Milky Way. Using IMACS/Magellan
spectroscopy, we identify 28 member stars of Eri IV and 34 member stars of Cen
I. For Eri IV, we measure a systemic velocity of and velocity dispersion . Additionally, we measure the
metallicities of 16 member stars of Eri IV. We find a metallicity of
and resolve a dispersion of
. The mean metallicity is marginally
lower than all other known ultra-faint dwarf galaxies, making it one of the
most metal-poor galaxies discovered thus far. Eri IV also has a somewhat
unusual right-skewed metallicity distribution. For Cen I, we find a velocity
and velocity dispersion . We measure the metallicities of 27
member stars of Cen I, and find a mean metallicity and metallicity dispersion . We calculate the systemic proper motion, orbit, and the
astrophysical J-factor for each system, the latter of which indicates that Eri
IV is a good target for indirect dark matter detection. We also find no strong
evidence for tidal stripping of Cen I or Eri IV. Overall, our measurements
confirm that Eri IV and Cen I are dark matter-dominated galaxies with
properties largely consistent with other known ultra-faint dwarf galaxies. The
low metallicity, right-skewed metallicity distribution, and high J-factor make
Eri IV an especially interesting candidate for further followup.Comment: 25 pages, 11 figures, submitted to AAS journal
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